Certain rotary knobs are described, for example, in German Published Patent Application No. 101 39 693. According to German Published Patent Application No. 101 39 693, in the context of modern electronic devices in a vehicle that constantly offer additional functions with more and more options, multi-function operating elements, by which various functions of the connected devices can be performed, have been produced because of the limited installation space for the associated operating elements. European Published Patent Application No. 0 366 132 describes, for example, a multifunction operating device for motor vehicles, where function groups and individual functions are selected with the aid of a rotary switch, and where an ENTER function can be triggered, one and the same bidirectional rotary switch being used for selecting menus and individual functions. This rotary switch has click-stop positions, to which menus or individual functions are assigned, the ENTER function being able to be initiated by an axial motion of the rotary switch. Such a multifunction operating device is used, for example, to enter the destination of a navigation system. To this end, an alphanumeric keyboard is illustrated on a display unit, the user being able to move forwards and backwards in the alphanumeric keyboard with the aid of the bidirectional motion of the rotary switch. When the cursor is situated on the desired alphanumeric character, the latter can be selected by an axial motion of the rotary switch and transferred into the navigation system. German Published Patent Application No. 199 41 960 describes that an operating element can be designed as a cylinder, which is bidirectionally rotatable about its longitudinal axis and elastically movable with respect to the longitudinal axis.
For convenient operation, and in order to simplify operating haptics, German Published Patent Application No. 101 39 693 describes that a bidirectional rotary element be formed, having an axis of rotation extending in a direction essentially parallel to a vehicle-part surface. Using the bidirectional rotary element, a bidirectional preselection and/or selection of function groups and/or functions is made within a menu level. Selection of the menu planes is accomplished via a second operating device. The second operating device can be implemented by moving the bidirectional rotary element parallelly to the axis of rotation of the bidirectional rotary element. To form the second operating device, a further variant provides for the bidirectional rotary element taking the form of a rocker in the direction of the axis of rotation. Another solution provides a second operating-device, which has two operating elements that are preferably manipulable in a direction parallel to the axis of rotation of the bidirectional rotary element. The second operating device is situated on or at least partially in the bidirectional rotary element and constitutes a unit with the rotary element. In addition, the bidirectional rotary element is designed for preselection and/or selection in two directions on the indicating apparatus, and the second operating device is designed for selection in two further directions, preferably perpendicular to the selection directions of the bidirectional rotary element.
Also described in German Published Patent Application No. 31 04 384 is an electrical-unit switch having displays, where a counter records the circuit state brought about by manually operating a freely accessible rotary not, and supplies it to a stationary, electronically functioning display field in accordance with the count, the display field and the rotary knob being situated close together, and a switching contact, which is operated by an actuating shaft supporting the rotary knob, interacting with the counter. In this context, it is possible to look at the rotary knob and display at the same time, since the electronic display field is built into the rotary knob on its front end face, the electronic display field being supported by a connecting piece projecting above the rotary knob in the rearward axial direction, and the front end face of the rotary knob being essentially transparent all around.
In addition, a push-button switch having a housing and a switching part displaceably supported in it is described in European Published Patent Application No. 0 329 920. A pushbutton cap used as a manipulating element has a base part having a tubular extension latched to the switching part, and a removable, at least partially transparent, protective cap. An LED or LCD display element having at least one light-emitting diode and/or one liquid-crystal display is situated in a cavity delimited by the base part and the protective cap, the LED or LCD display element being essentially formed by a wafer that is right-angled in the sliding direction of the pushbutton cap, and even being provided with electrical terminals.
A rotary knob is also described in European Published Patent Application No. 0 771 681.